I was wrong about:
1. Erron Black being bad - When he first debuted during the combat cast, I thought he was going to be terrible. His gameplay reminded me of Styker/Joker archetype, which were both bad. I wanted to main him though cause, I love that design (Played Chris Redfield in MVC and Joker Injustice). But I was definitely wrong on him being bad.
2. Reptile being top tier and very popular - Reptile was my other most anticipated combat cast (Played him in MK9). After seeing his original form, I thought he would be super top tier. Nimble/ Stinky/ Deceptive all looked really good. His claw swipe was an overhead at the time, and stopping forceballs looked so OP (Reptile with his own ice clone). I remember everyone speculating that he would be extremely good despite not having a diverse variation system, and because of that I thought he would be one of the more popular characters. When the game came out, I never took in how meter dependant he would be, the claw no longer being a mix up but rather a safe move ender, and he relatively lower damage output mid screen. Reptile's first iteration was actually really bad, but through patching he got better. Although Reptile isn't top tier, he is one of the few MKX characters that I think sits at a perfectly 'balanced position'. which is great. He has a top tier toolset limited but his meter dependancy and damage output, which makes him fair. He is also not being used by many people which I find surprising (it might be because many people are off put by his 'reptile' design). I reckoned he'd be at least as popular as Ermac.